Carburetor



April 6, 1937. SElGNO L ET AL CARBURETOR Filed Jan. 11, 1935 2Sheets-Sheet 2 [nvenlors Patented Apr. 6, 1937 UNITED STATES PATENTOFFICE 2,076,354 CARBURETQR,

Edouard Seignol and Francis Monier, Paris,

France, assignors to Societe Auxiliaire pour le Developpementdlndustries Mecaniques S. A. D. I. M., Geneva tion of SwitzerlandSwitzerland, a corpora- 18 Claims.

This invention relates to a new arrangement for feeding internalcombustion engines.

In known arrangements fuel is fed to carburetors of internal combustionengines either from a gravity tank or a rear low placed tank, fuel fromthe latter being fed by a raising arrangement or a pump, and theexplosive mixture produced by the fuel passes through manifold beforearriving at the cylinder inlets.

The carburetor according to the present invention lifts the fuel from alow placed tank to a primary carburetting device in which fuel istransformed into a rich mixture, without any exhausting arrangement orpump or other mechanical device, and then feeds the engine directlywithout requiring a manifold. The atomization of the fuel effected intwo stages is perfect.

One float chamber and one fuel feed line only are thus sufficient forfeeding multiple secondary l carburetor units.

The elimination of the manifold gives a great increase of power, anappreciable economy of fuel and better feeding of the engine.

The primary unit may be supplied with hot air from one side of theengine. The secondary unit thus supplied with a hot rich mixture is lesssubject to the action of cold and allows the use of fuels less volatilethan pure petrol.

This carburetor is capable of operation whatever the position of thefuel tank may be, whether same is a gravity tank or is disposed at alower level than the carburetor, the primary unit in the latter casebeing mounted in such position above the tank that its raising capacityis not exceeded.

The primary carburetor unit may eventually feed only one secondary unitmounted on the usual manifold.

Various embodiments of the fuel raising carburetor according to theinvention are illustrated by way of example in the attached drawingswherein:

Fig. l is a sectional side elevation of one embodiment of fuel raisingcarburetor according to the invention. It illustrates the wholearrangement of a primary carburetor unit, a double pipe line and twosecondary units.

Fig. 2 illustrates a valve device mounted on the rich mixture and vacuumtubes connecting one primary carburetor unit to two secondary units.

Fig. 3 is a sectional detail view on a larger scale showing the detailsof the jet and its tube and of the choke tube.

Fig. 4 is a vertical sectional view through a secondary unit, showingthe pressure check fitted to the differential vacuum arrangement, alsothe starting device.

Fig. 5 illustrates the jet output curves.

Fig. 6 is a sectional view illustrating the arrangement for increasingthe vacuum in the upper part of the primary unit, in a constructionwhere the throttle valve is disposed at the entrance of the secondaryunit.

Fig. 7 illustrates the valve mounted on the differential vacuumarrangement in the construction where the primary carburetor unit feedsonly one secondary unit.

Fig. 8 is a vertical sectional view of a part of the secondarycarburetor unit, illustrating a form of engine speed control device.

In the following description like reference numerals indicate identicalparts.

Referring to Figure 1, the primary carburetor unit connected to the reartank I of a vehicle by a tube 2 comprises a fluid tight casing made intwo parts 3 and 3a. The needle valve 4, the lever 5 and the float 6control the supply of fuel to the float chamber 3 and keep the surfaceof the fuel at a constant predetermined level.

Centrally disposed in the float chamber 3 there is a primary atomizercomprising a chamber 1 communicating with the atmosphere through theopenings 8 and. the tube 9 which may be heated, a choke tube [0 and ajet I I communicating with the mass of fuel in the float chamber 3through the opening l2 and the filter l3.

The jet II is mounted in member l4 attached to the choke tube, the conel5 of which is applied to the seating I6 andforms a joint between thecentral chamber 7 and the float chamber 3. The openings I! are adaptedto allow atmospheric air admitted through pipe 9 to enter the choketube.

The engine suction is communicated to the upper part of the floatchamber through the tube I 8 and the tube l9 connects the choke tube Itto the throats'of the choke tubes of the secondary units.

The primary unit thus constructed is light and fluid tight, and anydislevelling of the vehicle has practically no effect on the action ofits jet.

This arrangement is not limited to its details and the primary unit maybe constructed in any other suitable manner employing equivalents of theparts mentioned, for example the improvement shown in Figure 6.

The rich mixture produced by the primary unit is conveyed to the throats20 of the choke tubes 2| of the secondary carburetors through slidablydisposed in a cylinder 32 and subject to i the action of a spring. 313.The tube. 34,. which is units coaxially with the choke tubes 2| there isan air control valve 26 comprising a conical part 27 the sides of whichare parallel to the converging portion of the choke. tubeand: a conicalpart 28, the apex angle whereof is larger than that of the conical part21.

The diameter of the base ofthe cone- 28 is preferably equal to thediameter of the throat 2i! of the choke tube 2| multiplied: by 2:. Thisair control valve is mounted on a tube 29 slidable in a guide 30 andintegral with a piston. 3|

openat its end35, transmits the vacuum obtaining in the choke tube intothe cylinder 32under the driving face of the piston 3l ,.whereby'thedegree 25 of opening of the air inlet valve 26 is controlled.

The calibrated opening. 36 brakes. the opening movement of the aircontrol valve and the valve 31' nullifies this braking in the closingdirection. If the piston actuating. the air control valve 26- isinverted as shown in Figure 1, said valve may be moved into its closingposition by gravity action or by a counterweight, and. the spring 33'may be omitted.

The whole represents arr air admission control device, which: has theproperty of. accurately proportioning at any degree. of its opening a.mixture of fuel and air of substantially the most favourablecomposition.

A throttle valve 32; disposed at the exit. of the carburetor andconnected to the accelerator by means of a lever 39 controls the speedof the.

engine.

At the slowrunning position,.the air' control valve 26 almost completelycloses the. entrance of the secondary choke tube 2| and. the amount ofair entering. therein is very small. The vacuum obtaining at the upperpart of the primary unit on the top of the fuel level issalmost asstrong as that obtaining at the tip of the jet and the output of thelatter, being almostcompletely checked by the larger differential.vacuum, is very. small and amounts to a slow running supply.

If the throttle valve is opened to a certain extent, the vacuum thusformed in the diverging part of the secondary choke tube will betransmitted to the driving: face of the piston of. the air control valve26 and thus this valve will open to an extent corresponding to the loadof the engine. The same vacuum will also be transmitted tothe upper partof the float chamber and the checking action on. the jet will: bereduced. in accordance The control of the slow running feed is obtainedby varying, by the means of the needle screw valve 49, the section ofthe by-pass- 4 connecting the vacuum concluitof: the secondarycarburetor unit and the carburetor outlet after the throttle valve.

Fig. 2 is a sectional view of the rich mixture or vacuum tubesconnecting the primary carburetor unit to multiple secondarycarburetors.

42' and 43 represent two flat valves mounted in housings 44 and 45 andadapted to be alternately applied to their seatings 46 and 41.

When there is suction in the direction of the arrow fl, the valve 42 isdrawn from its seat and becomes seated at 48, allowing the mixture to.pass into the channel 49. During this time the pressure in the channel58 is smaller and the difference of pressure obtaining upon the twofaces-of the valve causes same to be pressed upon its seating 45, andthus only the secondary unit connected to, the channel 49 will besupplied with mixture;

When the secondary unit connected to channel 49 has concluded itssuction and that connected to the channel. 5!! begins. its suction areversal takes place, the valve. 47. will. be applied. to its seat 44 bythe suction coming. from 5.0 and the valve 43 will move to 54, thesecondary unit con-- the end of the cylindrical. part. 52.. The tube 55-terminates in the diverging part 54. of the choke tube it! at suchdistance from the cylindricalpart 52 thereof whichmay be varied to suitvarious typesof. engines. the shorter said distance will be and viceversa.

The operation of. this arrangement is as follows:

During the slow running ofthe engine the difference of vacuum betweenthe openings 56 and the end 57 of the tube 55 increases and a gaseousflow opposed to the flow of the fuel. is

formed in the tube. 55 and checks the output of the openings 56. untilthe output of these openings becomes insuificient. and the fuel risesinthe tube 55 upv to its end 51. for feeding the engine at.

higher speeds.

The calibration of the openings 56 will thereforetpermit modifying. theoutput curve of the jetv at willand if their total area is larger thanthe jet area the tube 55 will intervene by its end 51' to control theoutput of the openings 56 for the: whole output curve of the jet.

Fig. 5 illustrates the output curves of the jet.

A. is the output curve obtained prior to controlling. the differentialvacuum.

B isthe output curve of the same jet with control of the differentialvacuum.

C is the output curve of the jet with the control of-ti edifferentialvacuum and. of the openings 56, so that the end. 51- of thetube 5.5 intervenes in. the control of. they jet. output at all speedsof the engine.

D is. the output curve of a jet arrangement wherein the openings 56 areof such area that the output of. the jet is checked at low speeds up tothe moment when said area becomes insufficient, whereupon the end 5? ofthe tube 55: directly supplies the fuel.

Fig. 4 i's-a sectional view of a partof a second- The flatter the. jetoutput curve.

ary carburetor unit and shows details of an improved starting devicecomprising a tube 58 snugly rotatable in a bore 59 and having openingsEli and El which may be brought into register with the channels 62 and63 respectively.

The tube 53 is secured to a lever 64 which may be operated from thedrivers seat.

The operation is as follows:

When starting, the throttle valve 38 being closed, the driver operatesthe lever 64 connected to the tube 58 and brings the openings 69 and 61into register with the channels 52 and E53 respectively.

The very high vacuum obtaining on the engine side of the throttle valve38 is. transmitted thlough the channel 53 into the tube 58 therebydrawing in directly the very rich mixture from chamber 23 of the choketube.

The calibrated opening 65 disposed at the end of tube 58 allowssufhcient air to enter to render the mixture explosive and by dynamicshock produced umn the gaseous column completes the ifferentialautomatism of the device.

The starting device may also comprise a throttle valve t6 disposed atthe entrance of the s-condary carburetor units, as shown in Fig. 1. Whensaid throttle valve is closed the vacuum in the choke tube of theprimary unit is considerably increased and as a consequence adifferenceof vacuum is established which substantially corresponds tofull engine speed. The jet will then deliver at its maximum capacity andas only a very small quantity of air is admitted owing to the throttievalve being closed, the resulting very rich mixture will assureinstantaneous starting.

Fig. 4 also shows the pressure check 6? adapted to prevent the backflows of the secondary units from becoming effective upon the upper partof the float chamber, so that the jet output should no longer beaffected by said back flows.

The valve may be placed at the entrance of the carburetor, thusintensifying the action of the first choke tube and consequently thefuel raising, but this effect requires an arrangement for increasing bya suitable corresponding value the vacuum transmitted by the secondaryunit to the upper part of the float chamber of the primary unit.

This arrangement shown in Figure 6 takes the place of the connection ofpipe Hi to the secondary carburetor shown in Figure 1, and has a conicalbore 68 wherein is centrally disposed a tube extending the vacuum pipel8 and communicating with the secondary choke tube 2i, through thechannel l8, the chamber 25 and the apertures E l. Apertures ii areprovided to enable atmospheric air to enter the conical bore and thechannel it. This device increases the vacuum in the tube 58 after theair has reached a certain speed in the conical bore 58, while at smallspeeds the vacuum in the tube 69 is substantiaily equal to that in thechamber 2&5.

Di g starting a ring l2 closing the air inlet open igs Zi puts thisdevice out of action.

7 shows the valve '53 which, when the primary unit feeds only onesecondary unit, permits the flow from the primary unit to the secondaryunit but closes in the opposite direction, thus making all back flow tothe primary unit impossible.

8 illustrates a form of speed control device in vertical sectional view.The air control valve 26, which is hollow inside, is mounted on the tubei which is integral with the piston 3i sliding in the cylinder 32 andsubject to the action of spring 33. An air inlet funnel 15, whose freesection between its walls and the tube 14 is substantially equal to theexit of the carburetor, is disposed coaxially around the tube 14 underthe air control valve. The operation is as follows:

When the air entering the secondary carburetor through the openings itand the funnel 15 ex-.

ceeds a certain value, the underface of the valve 26 reduces the freespace between the valve and the funnel, owing to the valve approachingthe trally disposed chamber in the primary unit having communicationwith the atmosphere, a choke tube in said central chamber having aconstricted section forming a throat and an air entrance below saidthroat to receive air from the central chamber, a jet disposed coaxiallywithin said choke tube having its lower end in communication with thefloat chamber to receive fuel therefrom and its upper discharge endterminating at a level with said throat section, a secondary unitincluding a choke tube having a constricted section forming a throat anda diverging wall section extending from the throat towards the dischargeend of the choke tube. a conduit for conducting fuel from the choke tubeof the primary unit to the throat section, of the choke tube of thesecondary unit,a throttle valve for controlling the discharge of fuelfrom said secondary choke tube, means for admitting air to the other endof said secondary choke tube, a

valve adapted to control the delivery of air into said secondary choketube from said means, said valve being formed integrally with a pistonslidable in a cylinder and provided with a tube extending through thethroat section into the diverging wall section so as to transmit thevacuum pressure at this point to the working face of the piston, saidvalve being responsive to the vacuum acting on the piston to open andgradually retract the entrance of said tube to a position opposite saidthroat section, a second conduit joining the upper level of the primaryunit with said divergent wall section of the secondary unit therebysubmitting the upperlevel of the primary unit to a lesser vacuum thanthat transmitted by the other connecting conduit to the primary choketube.

2. A fuel raising carburetor for internal combustion engines comprising,in combination, a primary fuel raising, unit including a fluid tightconstant level float chamber communicating with a source of fuel toreceive fuel therefrom, a centrally disposed chamber in said floatchamber having communication with the atmosphere, a choke tube disposedin said central chamber provided with a constricted portion forming athroat and an opening below said throat to admit air from said centralchamber, a fuel jet disposed coaxially within said choke tube, said jethaving its lower end in'communication with said float chamber to receivefuel therefrom and having its upper discharge end terminating at a levelwith said throat, a plurality of secondary carburetor units each havinga choke tube provided with a constricted portion forming a throat, athrottle valve in the discharge end of each of said secondary choketubes, a vacuum controlled valve for each of said secondary choke tubesoperable to open and close the other end of each of said choke tubes toatmosphere, said throat portions of each of said secondary choke tubesprovided with a fuel inlet, a conduit for delivering fuel from saidprimary choke tube and provided with branch sections for delivering fuelindividually to each of said fuel inlets, a second conduit extendingfrom the upper level of the primary unit and provided with branchsections each communicating with one of said secondary choke tubes, saidbranched sections each provided with a valve member responsive to thedifferential pressure existing in said conduits to open and close eachof the branch sections to their respective secondary unit.

3. A fuel raising carburetor for internal combustion engines comprising,in combination, a primary fuel raising unit, a plurality of secondarycarburetor units, a fuel delivery system connecting said primary unitwith said secondary units and comprising a conduit extending from theprimary unit and branched to deliver fuel individually to each secondaryunit, an air conduit likewise connecting said primary unit with saidsecondary units and branched similarly to provide individuallycommunication with each secondary unit, each of said branch conduitsbeing controlled by a valve responsive to the differential pressureexisting in said conduits to open and close communication between theprimary unit and each of said secondary units.

4. A fuel raising carburetor for internal combustion engines comprising,in combination, a primary fuel raising unit, a plurality of secondarycarburetor units, a conduit extending from said primary unit andprovided with branched sections each leading to one of said secondaryunits, a valve longitudinally movable in each branch section andoperable in one position to close the branch section and in another toopen the branch section, each of said valves being responsive to thedifferential pressure existing in said conduit system on either sidethereof to shift to closing or opening position.

5. fuel delivery system for an internal combustion engine comprising, incombination, a primary fuel raising unit having a choke tube providedwith a constricted portion forming a throat, a secondary carburetor unitlikewise having a choke tube provided with a constricted portion forminga throat, a fuel jet mounted coaxially within said primary choke tube,said fuel jet communicating at its lower end with the fuel content ofsaid primary unit and extending upwardly within said choke tube at leastas far as said throat, means for admitting air into said primary choketube, and means for delivering fuel from the primary choke tube to thethroat of the secondary choke tube.

6. A carburetor device comprising, in combination, a primary fuelraising unit, a secondary carburetor unit, said primary unit having achamher for receiving fuel and a float controlled valve for controllingthe admission of fuel to the chamber, a choke tube in said chamberhaving a constricted portion forming a Venturi throat and diverging wallsections on either side of the throat, means for delivering air to thechoke tube below the Venturi throat, a tube mounted coaxially withinsaid choke tube having communication at its lower end with said chamberto receive fuel therefrom, said tube extending upwardly within saidchoke tube and having its discharge end terminating substantiallyopposite said Venturi throat section, said secondary carburetor unitlikewise provided with a choke tube having a Venturi throat, and aconduit connecting the two choke tubes and operable when subatmosphericair pressure exists therein to entrain fuel from the primary choke tubeto the secondary choke tube.

'7. A carburetor device comprising, in combination, a primary fuelraising unit a secondary carburetor unit, said primary unit having achamber for receiving fuel and a float controlled valve for controllingthe admission of fuel to the chamber, a choke tube in said chamberhaving a constricted portion forming a Venturi throat and diverging wallsections on either side of the throat, means for delivering air to thechoke tube below the Venturi throat, a tube mounted coaxially withinsaid choke tube and having communication at its lower end with saidchamber to receive fuel therefrom, said tube extending upwardly throughthe Venturi throat and terminating in the diverging wall sectionthereabove, said tube provided with an opening opposite the Venturithroat where the maximum vacuum is encountered, said secondarycarburetor unit likewise provided with a choke tube having a Venturithroat, and a conduit connecting the two choke tubes and operable whensub-atmospheric air pressure exists therein to entrain fuel from theprimary choke tube to the secondary choke tube.

8. A carburetor device for an internal combustion engine comprising, incombination, an air passage having a constricted section forming aVenturi throat, a throttle valve in said passage controlling thedischarge therefrom, means for delivering fuel into said air passage atthe level of said throat, a by-pass for delivering a rich mixture offuel to said passage beyond the effective position of said throttlevalve including a rotatable tube extending lengthwise of said passage, afuel conduit communicating with said fuel delivery means and saidrotatable tube and adapted to deliver a rich mixture of fuel from theformer to the latter, a fuel conduit extending from said tube to the airpassage on the side of said throttle valve remote from said throat, saidtube having ports adapted in one position of its rotation to communicatewith said fuel conduits, means for rotating said tube, and means forintroducing air into said tube in a direction opposing the flow of fuelbypassed therethrough.

9. A starter control device for a carburetor of an internal combustionengine having a fuel passage and a throttle valve controlling thedischarge of fuel through said passage comprising a tube positioned forrotatable movement adjacent said passage and provided with ports adaptedin one position of the tubes rotation to communicate with the passage oneither side of said throttle valve for the purpose of by-passing fueltherearound, said tube having an air inlet arranged to direct air intosaid tube in a direction opposing the flow of fuel by-passed through thetube.

10. A fuel raising carburetor device for an internal combustion enginecomprising, in combination, a chamber having a fuel inlet for receivingfuel and means for controlling the admission of fuel to maintain aconstant level of fuel therein, means for raising fuel above the levelof the fuel in said chamber comprising a series of tubes mountedcoaxially with respect to one another and in spaced relationship to oneanother, the outer tube forming an air tube adapted to deliver air belowthe level of the fuel in the chamber, a choke tube within said outer airtube having a constricted portion forming a Venturi throat passage andcommunicating with the outer air tube below the Venturi throat forreceiving air therefrom, and a third tube within said choke tubecommunicating with the fuel in the chamber at its lower end andextending upwardly in the choke tube at least as far as the Venturithroat section, said third tube adapted when sub-atmospheric pressureexists in said choke tube to entrain fuel upwardly therethrough anddischarge the same into the choke tube where it mixes with the airtherein.

11. A fuel raising carburetor device for internal combustion enginescomprising, in combination, a chamber having a fuel inlet for receivingfuel and a fioat for controlling the admission of fuel through theinlet, said float provided with a hole extending therethrough, an airtube positioned within the hole in said float and communicating at itsupper end with the atmosphere, a choke tube of less diameter than saidair tube posi tioned coaxially within the latter in spaced relation tothe said walls thereof, said choke tube having a constricted sectionforming a Venturi throat and an opening below the Venturi throat toadmit air from said air tube, and a fuel pipe positioned coaxiallywithin said choke tube communicating with the fuel in said chamber atits lower end and extending upwardly within the choke tube at least asfar as said Venturi throat section.

12. A fuel raising carburetor device for an internal combustion enginecomprising, in combination, a fuel chamber having a fuel inlet forreceiving fuel and means for maintaining a constant level of fueltherein, a choke tube in said chamber extending below the level of thefuel and provided with a constricted section forming a Venturi throat,means for delivering air to said choke tube below said Venturi throatsection, a tube mounted co-axially within said choke tube havingcommunication with the fuel content of said. chamber at its lower endand having its upper discharge end terminating within said choke tube ata point above said Venturi throat section, said last mentioned tubeprovided with an opening opposite the Venturi throat section, saidsecond tube adapted when sub-atmospheric ii pressure exists in saidchoke tube to entrain fuel upwardly therethrou h and mix the same withthe air in the choke tube as it is discharged therefrom.

13. A fuel delivery system for an internal combustion engine comprising,in combination, a constant level primary carburetor unit and a throttlevalve controlled secondary carburetor unit, a fuel conduit connectingsaid units together and adapted when sub-atmospheric pressure existstherein to conduct fuel from the primary unit tothe secondary unit, saidconduit having one section thereof in the form of a tube of lessdiameter than the conduit and extending longitudinally within theconduit for a short distance in spaced relation to the wall of theconduit, means for admitting air through the conduit and into the spacesurrounding said tube, means for regulating the amount of air soadmitted, and means for causing the admitted air to pass the dischargeend of said tube under relatively high velocity so as to increase thevacuum at this point.

14. A carburetor starter device for an internal combustion enginecomprising, in combination, a fuel passage, a throttle valve in saidpassage con trolling the flow of fuel therethrough, a fuel conduit forby-passing fuel around said valve having communication with said passageon one side of said valve to receive fuel therefrom and havingcommunication with said passage on the other side of said valve todischarge fuel thereinto, said fuel conduit having a constantly openedcalibrated air port arranged to admit air into the conduit in adirection opposing the flow of fuel lay-passed therethrough and meansunder manual control for simultaneously opening and closing both of saidcommunications between said conduit and said passage.

15. A fuel raising carburetor for internal combustion enginescomprising, in combination, a primary carburetor unit including aconstant level fuel chamber communicating with a source of fuel toreceive fuel therefrom, an air intake into said chamber, a choke tubedisposed in said air intake, said choke tube provided with a constrictedportion forming a throat and an opening below said throat to admit airfrom said air intake, a fuel jet disposed coaxially within said choketube, said jet having its lower end in communication with said floatchamber to receive fuel therefrom and its upper discharge endterminating within the length of said choke tube, a secondary carburetorunit including a choke tube provided with a constricted portion forminga throat, means for admitting air to one end of said secondary choketube, a vacuum controlled valve for controlling said last means, athrottle valve for controlling the flow of fuel through said secondarychoke tube, and means establishing communication between said primaryunit and said secondary unit including a conduit for delivering fuelfrom the choke tube of said primary unit to the choke tube of saidsecondary unit, and an air conduit connecting the upper interior levelof said primary unit with the choke tube of said secondary unit andprovided with a valve responsive to differential air pressures in theconduit to open and close the same in accordance therewith.

16. A fuel raising carburetor for internal combustion enginescomprising, in combination, a primary carburetor unit, a secondarycarburetor, a fuel delivery conduit extending from said primary unit tosaid secondary unit, an air conduit likewise connecting said primaryunit with said secondary unit, and a valve in said air conduitresponsive to differential air pressures existing therein to open andclose communication between said primary unit and said secondary unit.

17. A fuel raising carburetor for internal combustion enginescomprising, in combination, a primary carburetor unit, a secondarycarburetor unit, a conduit extending between said primary unit and saidsecondary unit, a valve member longitudinally movable in said conduitand operable in one position to close said conduit and in anotherposition to open said conduit, said valve being responsive todifferential pressures existing in said conduit to move to either anopen or closed position.

18. A fuel delivery apparatus for an internal combustion engine having aclosed substantially constant level fuel chamber and mixing chamber towhich fuel in said constant level cham her is delivered, an air conduitcommunicating between said mixing chamber and the interior sensitive todifferential air firessures existing inof said constant level chamberabove the level saidcpnduit to assume either the open or closed of thefuel therein, a valve element fioatingly position in accordancetherewith. mounted in said conduit and operable in one 5 position toclose the conduit and in another EDOUARD SEIGNOL. 5

position to open the conduit, said valve being FRANCIS MONIER.

